The present invention relates generally to the field of underwater diving, and in particular to a method and apparatus, utilizing the Global Positioning System (GPS) to provide underwater divers with navigational information.
In the field of underwater diving, it is sometimes difficult for a diver to accurately navigate between various locations or points of interest while submerged. One factor limiting a diver""s ability to navigate with any degree of precession is poor visibility. Poor visibility can greatly reduce the ability of the diver to successfully descend from a dive boat or shore location and return confidently to the same location on their ascent. Furthermore, it can be very difficult for a diver to navigate between geographically separated underwater locations of interest when the diver""s visibility of the locations is obscured.
The diver""s currently recognized method of navigation involves the use of an underwater compass. This necessary underwater diver navigational tool, while greatly useful for indicating direction, can be of little use to a diver over great distances or after several directional changes in course. Small errors in directional travel can result in the diver being a large distance from the intended target location. While a diver can in some instances ascend to the surface to regain their directional baring, this in most cases can be extremely dangerous due to surface obstructions such as watercraft.
Another limiting factor to the success of a diver""s navigation is time, which directly correlates to the diver""s finite air supply. The more time that is spent navigating to and from various underwater locations, the more air that is used by the diver. While a diver""s air use may vary greatly depending on various other factors, efficiently navigating between underwater locations will result in a diver using less air, thus enabling the diver to extend the quantity of bottom time spent at each underwater location.
Various devices have been designed attempting to overcome some of the navigational limitations listed above including U.S. Pat. No. 5,187,871 to McDermott (1993), which discloses an underwater navigation device incorporating a compass into a diver""s facemask. As stated above, while the compass provides the diver with the ability to determine their heading, when used over large distances small navigational errors can result in large deviations from the desired course of travel and the desired destination.
Other prior art including U.S. Pat. Nos. 5,077,703 to Strauss (1991), 6,029,515 to Lahteenmaki (2000), 5,570,323 to Prichard (1996), 5,666,326 to Holzschuh (1997) provide for a method of underwater guidance based on a transmitter(s) that generate a signal, such as microwave or radio, to a receiver worn by the diver. Various methods are used to display to the diver the distance and direction from and to the transmitter. While this method will indicate the diver""s approximate position relative to the transmitter, it will not provide a diver their location in relation to multiple reference points. Additionally, the cost and complexity of the various transmitters and receivers is prohibitive to most recreational divers.
Still another prior art reference U.S. Pat. No. 5,406,294 to Silvey (1995) describes a floating antenna system that is deployed and retrieved by an underwater diver. The Silvey invention is intended to be released by a submerged diver, floated to the surface for signal receiving, such as a GPS signal, and then retracted back to the diver when no longer needed. Although this patent provides for a method of using GPS signals to assist in underwater navigation, it is designed to be deployed after the diver is submerged, rather than allowing the diver to descend with the antenna deployed and active. It is also a legal and safety requirement in various jurisdictions for a diver to dive with a dive float and flag deployed at all times. The Silvey patent does not allow for this type of deployment.
Still other prior art references including U.S. Pat. Nos. 3,944,967 to Acks (1976) and 3,986,161 to MacKellar (1976) describe systems for underwater navigation utilizing ultrasonic transmitters and hydrophone receivers. While this method will indicate the diver""s approximate position relative to the transmitter, it will not provide a diver their location in relation to multiple reference points without the addition of a transmitter for each additional reference point. Additionally, the cost and complexity of the various transmitters and receivers is prohibitive to most recreational divers.
Therefore, there is a need for a device and method for use by underwater divers to improve the accuracy of underwater navigation, while at the same time allowing for various legal and safety related diving requirements to be fulfilled.
In brief summary, the invention is intended to provide an underwater diver with a method and apparatus for accurately navigating between underwater locations including, to and from a dive boat or shore, or between waypoints plotted prior to the dive or entered in real-time, during the dive.
It is therefore an object of this invention to provide the underwater diver with a low-cost, lightweight, and easy to use apparatus with the ability to utilize Global Positioning System (GPS) location data, received by an antenna located on the surface of the water, and transmitted to a GPS receiver carried by the diver.
Accordingly, several objects and advantages of my invention are as follows:
to provide the underwater diver with an apparatus to indicate their submerged dive location at the surface of the water with a dive flag and float.
to provide an underwater diver with a method and apparatus for accurately navigating to and from the starting location of a dive.
to provide a device that will float a Global Positioning System (GPS) antenna and power supply on the surface of the water.
to provide an underwater diver with a submergible GPS receiver and display.
to provide an apparatus which will dispense and retract varying lengths of tethering signal cable between a GPS antenna and a GPS receiver and display.
to provide an underwater diver the ability to plot a submerged objects location, as well as to allow the diver to return to the plotted location on subsequent dives.
to provide a GPS receiver capable of visually displaying to the underwater diver their current location at all times.
to provide to the underwater diver a GPS receiver capable of visually displaying the location of a plurality of plotted coordinates in relation to the diver""s current location.
Further objects and advantages are to provide a method and apparatus for underwater diver navigation that are both portable and affordable to the recreational and professional underwater diver.
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.